The Internal Revenue Service (IRS) building in Washington. / Susan Walsh, AP

by Christopher Doering, USATODAY

by Christopher Doering, USATODAY

The Internal Revenue Service paid out more than $53 million to whistle-blowers in 2013 who turned in friends, family and co-workers.

In its annual report to Congress, the IRS said public tips led the agency to collect $367 million from people committing tax fraud, with just under 15% of that amount awarded back to whistle-blowers. The report said the IRS doled out 122 awards during the 2013 fiscal year.

The amount of money the agency annually gives to whistle-blowers fluctuates depending on how much it collects. In 2012, the IRS paid out $125 million, but the year before it only doled out $8 million.

In most cases, a 2006 law championed by Iowa Sen. Chuck Grassley, R-Iowa, requires the IRS to pay awards to whistle-blowers if information they provide leads to the collection of taxes, penalties and interest of more than $2 million. But because appeals can take time, a whistle-blower often is left waiting several years to collect their award after they have filed an initial claim.

Grassley said while he welcomes the IRS' efforts to get whistle-blower tips and make payouts, the progress being made is too slow.

"The agency should do everything it can to make these cases a priority," said Grassley. "My worry is that the slow progress will cause the tips to dry up. That would harm the whistle-blowers who stick their necks out to flag tax cheating and the honest taxpayers who pay what they owe and deserve tax fairness."

The IRS report said it received 9,268 whistle-blower claims last year, up from 9,239 in 2012.